This invention relates to a cathode ray tube manufacturing method for subjecting a component part of a cathode ray tube to a predetermined treatment, and also to a manufacturing apparatus.
In general, in a process for forming a phosphor film of a desired pattern on the inner surface of a panel as a component part of a cathode ray tube, first, a black film 12 of a predetermined pattern is formed on the inner surface of a curved glass substrate which constitutes a panel 11, as is shown in FIGS. 1 and 2. The pattern of the black film 12 is, for example, a regular arrangement of a large number of circular holes 13 as shown in FIG. 3.
The black film 12 is formed by to a resist coating step, an exposure step performed using a shadow mask, a developing step performed without the shadow mask, and a step for coating a black conductive substance called a xe2x80x9cdagxe2x80x9d, on the inner surface of the panel 11.
After that, phosphor films 14 of blue, green and red are provided in the holes of the black film 12 as shown in FIG. 4. Also in this case, a phosphor screen consisting of the phosphor films 14 of the three colors and having a desired pattern is formed by the coating step for coating phosphors of three colors, a step for combining the panel 11 with a shadow mask, an exposure step performed through the shadow mask, and a developing step performed without the shadow mask. The phosphor screen is finished after a filming step or an aluminum forming step in which an aluminum film 15 is provided by sputtering.
In the above-mentioned phosphor screen forming process, however, it is possible that various types of defects will occur. For example, unless the panel temperature is kept at a desired value before exposure, the light radiation position may change due to thermal expansion of the panel at the time of exposure, thereby changing the landing position of each electron beam on the phosphor films. As a result, quality degradation may occur wherein sufficient white uniformity (WU), which should be obtained when blue, green and red are simultaneously lit, cannot be obtained.
Further, in the developing step, the phosphor films are developed by spraying a developer from a nozzle on the phosphor films. If the spraying pressure of the developer is very high, part of the phosphor will be removed to excess. This may reduce the thickness of the phosphor film to thereby degrade its brightness, or may peel off necessary part of the phosphor.
On the other hand, if the spraying pressure of the developer is very low, a defect, so-called a mixture of colors, will occur in which a desired color is mixed with another color. Moreover, if the spraying pressure of the developer varies with time or position of the phosphor film, the developer cannot be applied uniformly.
As described above, both the spraying pressure and temperature of the developer are important factors which will influence the development, and the viscosity, density and temperature of phosphor are regarded as important factors for forming a phosphor film. Accordingly, in order to form a phosphor film of a high quality, it is important to set, constant, manufacturing conditions such as the panel temperature assumed when coating the panel with phosphor, the viscosity, density and temperature of phosphor, the temperature and spraying pressure of the developer, the panel temperature assumed at the time of exposure, the temperature, humidity and purity of the atmosphere in the manufacturing room, etc.
The quality of the manufactured phosphor surface is usually inspected at the outlet of the phosphor film forming apparatus. This inspection is performed manually, with to-be-inspected panels placed on a panel conveyor or on an illuminated table onto which the panels are transferred from the conveyor. However, by manual inspection, it is very difficult to determine the cause of a defect in the film when it is found. Since there are so many factors that can be considered the cause of the defect, it is very difficult even for skilled engineers or workers to determine it.
It is an object of the present invention to provide a method for manufacturing a cathode ray tube, which can easily detect the cause of a defect, if it is found in a structural element of the tube.
It is another object of the present invention to provide an apparatus for manufacturing a cathode ray tube, which can easily detect the cause of a defect, if it is found in a structural element of the tube.
According to an aspect of the invention, there is provided a method of manufacturing a cathode ray tube, comprising the steps of: automatically setting peculiar information to a structural element of a cathode ray tube; performing one or more treatments on the structural element of the cathode ray tube; automatically measuring a treatment condition in the treatment step; automatically storing a measurement value obtained in the measuring step to couple the value with the peculiar information; and inspecting the structural element obtained in the treatment step to determine whether or not the structural element is defective.
According to another aspect of the invention, there is provided a method of manufacturing a cathode ray tube, comprising the steps of: automatically setting peculiar information to a panel of a cathode ray tube; performing a plurality of treatments on an inner surface of the panel of the cathode ray tube, thereby forming a phosphor film pattern on the inner surface; automatically measuring a treatment condition in the phosphor film pattern forming step; automatically storing a measurement value obtained in the measuring step to couple the value with the peculiar information; inspecting the panel obtained in the treatment step to determine whether or not the panel is defective; and automatically storing a defectiveness code to couple with the peculiar information if the panel is determined to be defective.
According to a further aspect of the invention, there is provided an apparatus for manufacturing a cathode ray tube, comprising: means for automatically setting peculiar information to a structural element of a cathode ray tube; means for performing one or more treatments on the structural element of the cathode ray tube; means for automatically measuring a condition of the treatment performed by the treatment means; a controller for automatically storing a measurement value obtained by the measurement means to couple the value with the peculiar information; and means for inspecting the structural element treated by the treatment means to determine whether or not the structural element is defective.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.